Control system for sound reproduction and recording apparatus



A ril 24, 1951 F. H. FODOR 2,550,007

CONTROL SYSTEM FOR SOUND REPRODUCTION AND RECORDING APPARATUS Filed April 9, 1949 uaouooaa J INVENTOR. FERENZ H. FODOR Patented Apr. 24, 1951 UNITED STATES PATENT OFFICE "CONTROL SYSTEM'FOR SOUND REPRODUC- TIUN AND RECORDING :APPAR'ATUS Ferenz H. Fodor, Los Angeles, Calif., assignor to Filmtone, -Inc., Los An tion of California geles, Calif., a-corpora- Application April 9, 1949, SerialN0. 86,416

14 Claims. .1 The present invention relates generally to a control system for ithesoperation of sound reproducing and recording apparatus of the type utilizing a, record strip or ribbon of suitable material uponwhich a sound track may be impressed-and which can thereafter be transcribedand audibly reproduced.

Apparatus .of the above character is :disclosed in detail .and specifically described in my Patent No. 2,254,478,.entitled, Method of Sound Reproductionand Apparatus'Therefor, issued September 2, 1941; and improvements in such-apparatus as disclosed in my co-pending application entitled, sound Reproduction Apparatus, Serial No.

film is moved through apparatusincludin transcribing means which may consist of alight source and reproducing pick-up, and means are provided whereby the film or other instrumentality automatically causes direction of travel of the film to be reversed at the end of a sound recording and a relative shifting of a scanning beam so as to cause the scanning'beam to be directed through an adjoining or desired sound record track onto the reproducing pick-up.

The present invention contemplates improvements in the control which will give improved automatic operation in shifting from one sound track to the next, and in reversing the direction of strip travel at the end of each sound track, and in which a novel arrangement'is providedfor indicating which sound track .is being transcribed.

Another objectof the invention is'to provide in control for such apparatus means whereby the automatic control may be supplemented by manual control by which the direction of travel of the record strip may be changed at will,'and the particular sound track desired selected at will. Such control is especially advantageous forediting purposes, and in connectionwith such operations as cuing, erasing or modifyingpor- .tions of the sound track, and for the purpose of introducing sound effects at a selected point in the sound track record.

vI-Ieretofore, it has been extremely difiicult to .pickout and determinespecific points in a sound .trackrecord, at which it may be desiredto modify as by erasing or ,by introducing other :sound effects. Further, when a desired point of change 'Was located, ,difliculty was experienced :in endeavoring to apply the particular modification or change at the point desired. With the foregoing in mind, it is a iurtherobject of the present invention ,to provide an electronically controlled relay f orstopping the strip driving means upon the occurrence of a predetermined characteristic in the sound track which may result from .a transition between a recording section anda nonrecording section inthe'sound track or :from a change resulting from -a particular recorded aeffect such as a whistle, scream -or the like. Recording zmeanstincluding .a rack-over relay-are provided 'so :that there will becoincidence :of :the

:point of stoppage or. starting of thestrip andfthe recording mechanism, thus enabling the insertion of-desired soundeffects or other modificationsto be obtained at a particularly desired point ,in

the sound trackzof the-record.

Furtherobjects of the invention Will be brought out in the following part of the specification, wherein detailed description is for .the purpose of.fully disclosing theinvention without placing limitations on thescope of the invention defined in theappended claims.

Referring tothe drawings, which arelfori'illustrative purposes only:

.Fig. 1 is aschematic wiring diagram ,ofacontrol system embodying the features-of the present invention; and

Fig. 2 is a fragmentary representation ,ofa soun'drecordstrip, showing portions of the sound track'having a pertinent bearing onthe operation of the present invention.

Apparatus ingen'eral Apparatus as described in detail in my above patent and co-pending application has been, disclosed in the present applic'ation' in a schematic manner in order that the associated control system and its connection with the'various elements of ,theapparatus will be clear.

'[In general, the apparatus withwhich the control system of the present invention is utilized, comprises a rotatable drum In of hollow construction, this drum being arranged to support on its periphery a sound record strip or ribbon l I containing one or more parallel sound tracks. This strip is uided onto the drum by associated rollers l2l'2'in spaced apart relation at the top of the drum.

While the present invention contemplates that the record strip may'be of any of the well known -"-tric cells ['9 and types of construction, and a sound track embodying any of the recognized arrangements for modulating suitable pick-up means by which the sound record may be transcribed and audibly reproduced, for purposes of illustration the strip is disclosed as being of the type in which a variable area sound track is' impressed upon a film strip or ribbon in conventional manner, so that a scanning light beam may be utilized in connection with the pick-up means.

In the present instance, there is shown a light source l3 which is projected through a suitable optical system as represented by the numeral Hi, in a direction toward the center of rotation of the drum In so as to pass through the record strip at the bottom of the drum It.

The scanning beam passes into a prism as-- sembly l5 which constitutes a light divider which serves to separate the scanning beam passing along a single axis l6 into portions passing along "parallel axes Wand l8 to individual photo-elec- 25, respectively.

" Positioned between the light source [3 and the --strip on the drum it are masking means including a plurality of adjacently disposed masking {elements 21 in side-by-side relation transversely of the record strip, each-of the masking elements containing an aperture 22 which willpermit passage of light therethrough when moved to the axis I6, but the masking element preventing passage of light along the axis l6 when the aperture -22 is displaced to one side of its axis.

-Means are provided for successively shifting the masking elements in longitudinal direction in order to control the passage of light along the *axis 16, and provide in efiect a relative lateral shifting of the strip and scanning light beam "transversely of the strip to transcribe the respective sound tracks. Each masking element is con- "nected through a bell crank 23 or other suitable motion transmitting means with a movable core member 24 of a solenoid having an actuating coil 25, a coiled spring 26 being provided to normally bias the associated masking element in a directionnormally blocking passage of light along the axis 16, but permitting passage of light through the aperture 22 when the solenoid 25 is energized. The strip H is moved longitudinallyby means of the drum I0 which is connected with reversible drivingrneans as generally indicated by numeral 25, the driving means having a winding 25 adapted upon being energized to drive the drum .lll in a cckwise direction, and a winding 2'! adapted upon being energized to drive the drum in'a counterclockwise .direction. Also, operatively associated with the driving means is a .brake winding 28 adapted-upon being energized to apply electro-magnetic braking action to stop the drivin'g movement of the drum I0. 7

n I Soundtrack selector colntrol 'Theselection of sound track to be transcribed is accomplished by a stepping relay, as generally indicated at, 29, having an actuating coil 30 and 'a movable contact member 3! composed of three arms .32 injangular relation and each carrying a brush contact adapted to successively engage stationary contacts 33 in group-sectorarrange- 'ment; Thea'ctuating coil 30 has one terminal connected through'a' conductor 34 with one side35 of'an electrical source. The other terminal .of ,this coil. is connected by a conductor 36 through a push button 3'1 andmanually operable switch '38 to' the other side '39 of the electrical source.

The movable contact member 3| of the stepping relay 29 is connected by a conductor 40 with side 39 of the electrical source. The stationary contacts 33 of one group-sector are respectively connected by separate conductors 4| to corresponding terminals of indicating lamps 42 having their other corresponding terminals connected to a common conductor 43 which is connected to the other side of a suitable electrical source.

The stationary contacts 33 of the next groupsector are respectively connected through individual conductors with the corresponding ends of the actuating coils 25 for operating each of the masking elementsZl. The other ends of the coils 25 are commonly connected to a conductor 45 which connects through an energizing circuit with the other side 35 of the electrical source.

The control just described is utilized for selecting of the sound track which it is desired to transcribe. This may be done as follows: with the manually operable switch 38 in closed position, actuation of the push button 3'! acts to energize the coil 30 of the stepping relay 29 in conventional manner to advance its movable contact from one stationary contact 33 to the next of each group-sector each time the push button 37 is closed, whereby the indicating lampsdz will be successively connected in the order I to 6' as indicated, and the actuating coil 25 successively connected in the order I to 6 inclusive as indicated. It will therefore be apparent that by the simple manipulation of closing the push button 37 and observing which of the indicating lamps 42 is energized, it is a simple operation to pick out and select a desired sound track on the strip ll,

there being illustrated selector means in this in-- stance for six sound tracks.

Automatic progression control a a through a conductor 5| having a control switch 52 therein. A bleeding circuit containing a resistance 53 and condenser 54 is connected respectively across each set of contacts 48 and 49.

In the? normal condition of relay 46, the normally closed contacts :38 connect the brake winding.28 through an energizing circuit as follows: from side 35 of the electrical source, through conductor fiiL'normally closed contacts 48, conductor 55 to one side of the winding 28, from the other side of this winding by conductor 56, and thence through conductor 5! to the'side39 ofthe electrical source. 7 e

Thecontacts 4 9, in closed position, connect-one terminal of each of the windings 26 and 2'! with one side of the electrical source through the following circuit: common conductor 58, conductor 59, conductor 65, contacts 49 and conductor 50 which is connected to .side 35 of the electrical source. The other ends of the windings 26 and 21 are connected to alternate stationary contacts 33 of 'the third group-sector of the stepping relay by means of conductors 59 andli!) which connect to the movable contacts of a double-pole doublethrow switch 61 connectable in the upper throw thereof with conductors t2 and 63.

Operation of the automatic progress control is as follows: with the relay ltdeenergized and its contacts 48 closed, the brake winding 28 is energized to oppose driving movement of the strip I I. Having selected a particular track at which it is desired to start the automatic progressive transcription of the sound tracks, this selection having been accomplished by actuation of the push button 37 as previously described, switch 52 is then closed. Closure of switch 52 energizes the actuating coil 31 so that switch 46 will now close its contacts 39 and open its contacts 48, this action deenergizing the brake winding and connecting the windings 26 and 2? to one side of the electric source. With the switch El upwardly closed, the driving means 25 will start driving the drum II] in either a clockwise or counter-clockwise direction depending upon whether winding 26 or winding 2'! is connected to the group-sector contacts of the stepping relay. With the movable contact 3| in the position shown, winding 21 is connected so that the driving means will start operating in a counter-clockwise direction to transcribe sound track No. 1 as indicated by the indicating lamp I.

Whichever direction the strip II is traveling, the strip movement will continue until the end of the particular sound track which is being transcribed is reached, whereupon automatic reversing means are actuated for reversing direction of strip travel. This automatic reversal is accomplished by the provision of normally open switches 62'- 62' arranged for closing in response to the reaching of the end of a particular sound track being transcribed. The switches 62-S2' have their contacts in parallel, and the closure of either switch will operate to energize the stepping relay actuating coil 30 through the following circuit: from side 35 of the electrical source, through conductor 34 to one side of coil 30, through conduc'e tors 63 and 64, contacts of switch 62', and thence through conductor 65 to side 39 of the electrical source. It will therefore be apparent that one or the other of switches 62 will be actuated at the end of each sound track, and that at that point the coil 39 of the stepping relay 29 will be actuated, so that this relay then shifts to the next set of contacts to change the direction of operation of the driving means and automatically energize the coil 25 to shift the next masking element 2| to a position in which its aperture 22 will pass a Scanning light beam through the next sound track.

To discontinue automatic progression transcription, it is only necessary to open switch 52, which will deenergize the coil 41 of relay 36 and permit it to assume normal position with its contacts 49 open and contacts 48 closed. Opening of contacts. 59 will disconnect the windings 25 and 27, and closing of contacts 48 will connect brake winding 28 to bring the driving means to a quick stop.

Editing control During editing, erasing, cueing and at other times, it is of advantage to not only shift from one sound track to the other as previously explained in connection with track selection, but it is also advantageous to be able to manually control the direction of travel of the strip II at any desired point along the sound track between its ends. For such purpose, there is provided a single-pole double-throw switch 66 having its movable contact connected to side 39 of the electrlcal source. The other contacts of this switch are connected to the downward throw stationary contacts of switch BI, as shown, so that by connecting the switch 6| in its downward throw, conductors 62 and 63 are disconnected with respect to conductors 59' and 68; thereby disconnecting the automatic control of direction of strip travel by the stepping relay. Thus, in the downward throw of switch BI, switch 66 may be thrown in one direction or the other to connect conductors 59 or 60 so as to selectively energize the windings 21 and 26 to drive the strip I I in the desired direction.

Sounds efiects selector control The sound effects selector provides control instrumentalities which are so arranged as to automatically'stop the strip travel upon the occurrence of a predetermined characteristic in the sound track, for example, variations in voltage in a pick-up circuit which may be occasioned by a particular recorded sound effect such as a whistle, scream or the like, or changes which may result from passing from a recording section to a non-recording section of the sound track, or vice versa. As illustrative of such changes in sound track characteristics, there is shown in Fig. 2 a section of a sound record strip II containing a single sound track 61 thereon, the sound track in this instance being of the variable area type and having sections 68-68 which are representative of the sound track record which is formed during recording. The normal trace during times of non-recording is indicated by the numeral 69. It will be observed that the junction of a recording and non-recording section constitutes an abrupt definite change which will be reflected in a pick-up device.

In the present invention, provision is made for taking advantage of such changes in sound track characteristics, while at the same time reproducing a sound track record, by the provision of dual photo-electric cells I8 and 28 and the prism I5 which acts as a light divider to direct corresponding portions of the sound track along axes I1 and I8 to the pick-ups. Photo-electric cell I 9 is connected to the input of a pre-amplifier 10, a switch ll being provided for disconnecting this portion of the control, when desired. An output circuit of the pre-amplifier is connected to the primary side of an audio transformer 72 having its secondary connected in the input circuit I3 of a triode grid controlled electronic tube 14. The input circuit of the tube contains a blocking condenser '15, one side of this condenser being connected through a potentiometer 16 to the negative side of a C-battery. The other side of the condenser 15 connects with the movable contact of the potentiometer.

The plate of tube 74 is connected to an output circuit I? containing a balancing resistance It connected on one side through a blocking condenser I9 with the tube cathode and on the other side to the positive side of a B-battery through an actuating coil of a relay SI having nor mally closed contacts 82.

By utilization of a suitable adjustable potentiometer I6 and balancing resistance 78, grid current of the tube 74 may be reduced to the null point without disturbing the balance of the grid bias of the tube. It is thus possible to utilize an increasing or decreasing voltage resulting from sound track variations to control the flow of current in the output circuit of tube It in such manner as to cause an opening of contacts 82 or through a manually side of actuating coil 41 of relay 46 which is upon closing thereof depending upon which direction the grid bias is thrown.

The'starting of the apparatus when utilizing the sound effects selector, is accomplished by means of a relay 83 having a control coil 84 and conductor 81 containing a normally open push button switch 88. This side of coil 84 is also connected through contacts 86 and contacts 82 of relay 8| to an interlocking circuit conductor 89 connected with the side 39 of the electric source operable switch 90. The

connected to conductor is also connected by a conductor 9| through the contacts 85 of relay 83 to conductor 89.

Assuming that it is desired to now start the sound effects selector control, switch 90 is closed. Nothing happens at this point because the contacts 85 and 86 of relay 83 are in their normal open positions. Starting is now accomplished by closing the push button 88 which will energize relay 83 and cause it to close its contacts 85 and 86 and interlock itself in closed position through its contacts 86. Closing of contacts 85 puts current on the actuating coil 41 of relay 46 which will now operate to open its contacts 48 and release the brake on the driving means. Closure of contacts 49 connect one side of each of the windings 26 and 21 with one side of the electric source as previously explained, and direction of strip travel may now be either automatically controlled or controlled at will by closing the switch 6| in proper direction or by use of push button 31 or switch 66 to obtain the characteristic operation previously described by the use of these switches.

With the strip moving and being scanned by light beams passing along axis Hi, the occurrence of the predetermined change in characteristic of the sound track for which the grid current of tube 14 has been adjusted will cause current to flow in the output circuit of the tube and actuate relay 8| to open its contacts 82. Opening of these contacts interrupts the interlocking circuit of the actuating coil 84 of relay 83, wherethis relay will drop out and open its contacts 85 and 86. Relay 83 is thus locked out, and opening of'contacts 85 interrupts the circuit on relay 46 so that upon deenergization of its actuating coil 41 it will drop out and open its contacts 49 and close its contacts 48. As soon as contacts 48 are closed, the brake winding 28 is energized and causes substantially instantaneous stopping of record strip movement. With the control just described, it is therefore possible to interrupt strip movement at a particularly desired point at which it may be desired to modify the sound track record in some manner, such as by erasing, insertion of sound effects, or otherwise.

In order that further recordings may be made at theparticular desired point at which the strip movement was stopped, recording mechanism, as generally indicated at M, is provided including a conventional rack-over relay 92 having an actuating coil 93 which may be connected by a suitable switch 94 in multiple with the actuating coil 36 of the stepping relay 29. The rack-over relay will thus follow changes from one sound track to the other which may be accomplished by the stepping relay 29, and by disposing the track 'gizing one of "tracing element so that it will be coincident with the point at which the sound record strip H may be stopped during; the operation of the sound efiects selector control, changes and additions may be recorded on the record strip at the predetermined point of stopping.

I claim:

1. In an apparatus of the character described,

the combination of: means for supporting and advancing a record strip having a plurality of sound tracks thereon; pick-up means adapted to be modulated by a sound track on said strip; driviing means for said strip supporting and advancing means; automatic means controlled in responseto strip movement for reversing the direction of travel of said strip at the end of each sound track, and relatively shifting said pick-up means and said strip to operatively associate the pick-up means with a next adjacent sound track; and electrical means visually indicating which sound track is being transcribed. 2. In an apparatus of the character. described, the combination of means for supporting and advancing a record strip having a sound track thereon; driving means for said strip supporting and advancing means; means for transcribing said sound track; means for automatically revers'ing said driving means to change the direction of travel of said strip at predetermined points thereon, including an energizing circuit; braking means for stopping saiddriving means, including an energizing circuit; and means forenersaid circuits and deenergizing the other of said circuits.

3. In an apparatus of the character described, the combination of: means for supporting and advancing a record strip having a plurality of sound tracks thereon; pick-up means adapted to be modulated by a sound track 'on said strip;

driving means for said strip supporting and advancing means; sound track selector means actuatable for relatively shifting said pick-up means and said strip to change the sound track with which said pick-up means is associated; and readvancing a record strip having a plurality of sound tracks thereon; pick-up means adapted to be modulated by a sound track on said strip;

driving means for said strip supporting and advancing means; stepping switch means actuable for reversing the direction of travel of said strip at the end of each sound track, and relatively shifting said pick-up means and said strip to operatively associate said pick-up means with a next adjacent sound track; and recorder means in-- eluding a rack-over relay energizable simultaneously with each actuation of said stepping switch means.

5. In an apparatus of the character described, the combination of means for supportin and advancing a record strip having a sound track thereon; driving means for said strip supporting and advancing means including. a control circuit; pick-up means responsive to a characteristic of said sound track; a grid controlled electronic tube having an input circuit and an output circuit; means vfor impressing pick-up responses'on said input circuit; a relay having an actuating coil in said output circuit and contacts operatively associated with said control circuit; an adjustable potentiometer in the input circuit of said tube; and a balancing resistance inthe output circuit of said tube, said potentiometer and resistance being cooperatively adjustable to obtain a pre-determined grid bias upon the occurrence of a pre-determinable pick-up response.

6. In an apparatus of the character described, the combination of means for supportin and advancing a record strip having a sound track thereon; driving means for said strip supporting and advancing means including a control circuit; a plurality of pick-ups including a reproducing pick-up; means for projecting a scanning medium on said track; means for dividing said medium and directing the divided parts, one part to said reproducing pick-up and another part to another of said pick-ups; a grid controlled electronic tube having an input circuit and an output circuit; means for impressing responses of the latter pick-up on the grid of said tube;

a relay having an actuating coil in said output circuit and contacts operatively associated with said control circuit; and means for regulating the grid bias of said tube to actuate said relay upon the occurrence of a predetermined response from said latter pick-up.

7. In an apparatus of the character described, the combination of: means for supporting and advancing a record strip having a sound track thereon; driving means for said strip supporting and advancing means including a control circuit; .a pick-up; means for projecting a scanning beam on said track and to said pick-up; a grid controlled electronic tube having an input circuit and an output circuit; means for impressing pick-up responses on the grid of said tube; a relay having an actuating coil in said output circuit and contacts operatively associated With said control circuit; and means for regulating the grid bias of said tube to actuate said relay upon the 40 occurrence of a predetermined voltage response from said pick-up means.

8. In an apparatus of the character described, the combination of: means for supporting and advancing a record strip having a sound track thereon; driving means for said strip supporting and advancing means including a control circuit; pick-up means having a. voltage response to a characteristic of said sound track; a grid controlled electronic tube having an input circuit and an output circuit; means for impressing pickup responses on the grid of said tube; a relay having an actuating coil in said output circuit and contacts operatively associated with said control circuit; and means for regulating the grid bias of said tube to actuate said relay upon the occurrence of a predetermined voltage response from said pick-up means.

9. In an apparatus of the character described, the combination of means for supporting and advancing a record strip having a sound track thereon; driving means for said strip supporting and advancing means including a control circuit;

pick-up means responsive to a characteristic of said sound track; a grid controlled electronic tube having an input circuit and an output circuit; means for impressing pick-up responses on said input circuit; a relay having an actuating coil in said output circuit and contacts operatively associated with said control circuit; and means for adjusting the grid current in such manner as to control the actuation of said relay upon the occurrence of a predetermined pick-up response.

10. In an apparatus of the character described, the combination comprising: means for support- 10 ing and'advancing a record-strip 'havingia sound track thereon; driving means for said'strip supporting and advancing means; means for reversing direction of strip travel including afirst actuating circuit; means for stopping saidstrip movement includin a second actuating circuit; a relay having an actuating coil, closed contacts normally operable to energize said second circuit, and normally open contacts operable upon closing to energize said first circuit; an interlocking relay having normally closed contacts inan in terlocking circuit; a sound effects selector re-.

lay having anactuating. coil, and a pair of-nor mally open sets of contacts, one of said sets arranged to connect the actuating coil of said first relay with the interlocking circuit,zand the other set .to connect the actuating coil of the selector relay to the interlocking circuit through the interlocking relay contacts; switch means for 'initially energizing the actuating coil of the selector relay, whereby both the first relay'and the se lector relay are interlocked in energized condi tion to release the brake and connect the reversing means; and means responsive to a characteristic of said sound track for controlling the actuation of said interlocking relay to disconnect the reversing means and connect the braking means. i r I 11. In apparatus of the character described, the combination of: means for supporting-and advancing a record strip having a plurality of sound tracks thereon; pick-up means adapted to be modulated by a sound track on said strip; driving means for said strip supporting and advancing means; a multi-armed stepping relay, each arm being arranged to successively engage a plurality of stationary contacts arranged in a corresponding number of group-sectors; means having controlled circuit connected to and controlled by the contacts of a first group-sector for alternately reversing said driving means; means havin control circuits connected to and controlled by the contacts of a second group-sector for successively Qperatively associating with pickup means with said sound tracks; means having control circuits connected to and controlled by the contacts of a third-sector for successively indicating the sound track with Which the pickup means is associated; and means for energizing said stepping relay in response to movements of said record strip.

12. In apparatus of the character described, the combination of: means for supporting and advancing a record strip having a plurality of sound tracks thereon; pick-up means adapted to be modulated by a sound track on said strip; driving means for said strip supporting and advancing means; a multi-armed stepping relay,

each arm being arranged to successively engage I a'plurality of stationary contacts arranged in a corresponding number of group-sectors; means having controlled circuits connected to and controlled by the contacts of a first group-sector for alternately reversing said driving means; means having controlled circuits connected to and controlled by the contacts of a second group-sector for successively operatively associating said pickup means with said sound tracks; means having control circuits connected to and controlled by the contacts of a third group-sector for successively indicating the sound track with which the pick-up means is associated; means for energizing said stepping relay in response to movement of said record strip; and manually operable switch ping relay;

driving means for said ineans for independently energizing said stepcorresponding number of group-sectors; means having controlled circuits connected to and controlled by the contacts of a first group-sector for alternately reversing said driving means; means havin controlled circuits connected to and controlled by the contacts of a second group-sector ,for'. successively operativelyassociating said pickup means with said sound tracks; means for energizing said stepping relay in response to movement of said-record strip; and manually operable switch means for controlling operating directions of said driving means independently of the contacts of said second group-sector.

14. In apparatus of the character described, the combination of rmeans for supporting and 1 advancing a record strip having a plurality of pick-up means adapted I sound tracks thereon; to be modulated by a sound track on said strip;

strip supportin and advancing means; a multi-armed stepping relay,

v V 4 g I each arm being arranged to successively engage a plurality of stationary contacts arranged in a corresponding number of group-sectors; means having controlled circuits connected to and controlled by the contacts of a first group-sector for alternately reversing said driving means; means having controlled circuits connected to and controlled by the contacts of a second group-sector for successively operatively associating said pickup means with said sound tracks; means 'for energizing said stepping relay' in response to movement of said record strip; and auxiliary control means responsive to a soun track char-. acteris'tic for modifying the control of said driving means by said stepping relay.

FERENZ 1-1. FODOR. REFERENCES orrEn The following references are of record in the file of this patent: V

UNITED STATES PATENTS Number Name Date 2,069,631 Thomas Feb. 2, 1937 2,088,451 Thomas July 27, 193'? 2,215,468 Herzig Sept. 24, 1940 2,252,327 Love'tt; Aug. 12,1941 2,254,478 Fodor Sept; 2, 1941 2,351,005 Camras June 13, 1944 Berzer Mar. 12, 1946 

